Rodeo is a census-designated place (CDP) located in Contra Costa County, California, United States, in the East Bay sub-region of the San Francisco Bay Area, on the eastern shore of San Pablo Bay, 25 miles northeast of San Francisco. The population was 9,653 at the 2020 census. The place is named for the rodeos common in the late 19th century. Cattle from the surrounding hills were regularly driven down through the old town district to a loading dock on the shoreline of San Pablo Bay for shipment to slaughterhouses, a practice which continued through the early 20th century. Rodeo is served by the Interstate 80 freeway and State Route 4 and was formerly served by the first transcontinental railroad, which still passes through Rodeo. Rodeo has not been a stop on the railroad since the 1950s.